Semiconductor memory device and method of manufacturing the same

ABSTRACT

A connection unit is provided adjacently to the cell array unit and electrically connected to a peripheral circuit unit positioned downwardly of the cell array unit. The cell array unit has a configuration in which a variable resistance layer is provided at intersections of a plurality of word lines extending in a horizontal direction and a plurality of bit lines extending in a vertical direction. The connection unit includes a lower wiring line layer in which a base portion bundling a plurality of the word lines is formed, and a middle wiring line layer and upper wiring line layer formed upwardly thereof. The lower wiring line layer includes: a first penetrating electrode connecting the plurality of word lines and the peripheral circuit unit; and a second penetrating electrode connecting at least one of the middle wiring line layer and upper wiring line layer and the peripheral circuit unit.

CROSS REFERENCE TO RELATED APPLICATION

This application is based on and claims the benefit of priority fromprior U.S. Provisional Patent Application No. 62/045,970, filed on Sep.4, 2014, the entire contents of which are incorporated herein byreference.

FIELD

An embodiment described in the present specification relates to asemiconductor memory device and a method of manufacturing the same.

BACKGROUND

Conventionally proposed is a semiconductor memory device employing as astorage element a variable resistance element whose resistance valuechanges by application of a voltage. Moreover, conventionally known is athree-dimensional type memory cell array structure in which thepreviously mentioned variable resistance element is provided at anintersection of a first wiring line formed in a perpendicular directionto a substrate and a second wiring line formed in a horizontal directionto the substrate.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an overall block diagram of a semiconductor memory deviceaccording to a first embodiment.

FIG. 2 is a perspective view of external appearance of the semiconductormemory device.

FIG. 3 is a perspective view of external appearance of a memory cellunit.

FIG. 4 is a perspective view of external appearance showing part of acell array unit.

FIG. 5A is a plan view in which the cell array unit is viewed from above(an opposite side to a substrate).

FIG. 5B is a plan view in which the cell array unit is viewed from below(a substrate side).

FIG. 6 is a cross-sectional schematic view of the cell array unit.

FIG. 7 is a table showing applied voltages during operations.

FIG. 8 is a perspective view of external appearance of a connectionunit.

FIG. 9 is a planar schematic view of a lower wiring line layer.

FIG. 10 is a view showing a manufacturing process of the cell array unit(view No. 1).

FIG. 11 is a view showing a manufacturing process of the cell array unit(view No. 2).

FIG. 12 is a view showing a manufacturing process of the cell array unit(view No. 3).

FIG. 13 is a view showing a manufacturing process of the cell array unit(view No. 4).

FIG. 14 is a view showing a manufacturing process of the cell array unit(view No. 5).

FIG. 15 is a view showing a manufacturing process of the cell array unit(view No. 6).

FIG. 16 is a view showing a manufacturing process of the cell array unit(view No. 7).

FIG. 17 is a view showing a manufacturing process of the cell array unit(view No. 8).

FIG. 18 is a view showing a manufacturing process of the cell array unit(view No. 9).

FIG. 19 is a view showing a manufacturing process of the cell array unit(view No. 10).

FIG. 20 is a view showing a manufacturing process of the cell array unit(view No. 11).

FIG. 21 is a view showing a manufacturing process of the cell array unit(view No. 12).

FIG. 22 is a view showing a manufacturing process of the cell array unit(view No. 13).

FIG. 23 is a view showing a manufacturing process of the cell array unit(view No. 14).

FIG. 24 is a view showing a manufacturing process of the cell array unit(view No. 15).

FIG. 25 is a view showing a manufacturing process of the connection unit(view No. 1).

FIG. 26 is a view showing a manufacturing process of the connection unit(view No. 2).

FIG. 27 is a view showing a manufacturing process of the connection unit(view No. 3).

FIG. 28 is a view showing a manufacturing process of the connection unit(view No. 4).

FIG. 29 is a view showing a manufacturing process of the connection unit(view No. 5).

FIG. 30 is a view showing a manufacturing process of the connection unit(view No. 6).

FIG. 31 is a view showing a manufacturing process of the connection unit(view No. 7).

FIG. 32 is a view showing a manufacturing process of the connection unit(view No. 8).

FIG. 33 is a view showing a manufacturing process of the connection unit(view No. 9).

FIG. 34 is a view showing a manufacturing process of the connection unit(view No. 10).

FIG. 35 is a view showing a manufacturing process of the connection unit(view No. 11).

FIG. 36 is a view showing a manufacturing process of the connection unit(view No. 12).

FIG. 37 is a view showing a manufacturing process of the connection unit(view No. 13).

FIG. 38 is a view showing a manufacturing process of the connection unit(view No. 14).

FIG. 39 is a view showing a manufacturing process of the connection unit(view No. 15).

FIG. 40 is a view showing a manufacturing process of the connection unit(view No. 16).

FIG. 41 is a view showing a manufacturing process of the connection unit(view No. 17).

FIG. 42 is a view showing a manufacturing process of the connection unit(view No. 18).

FIG. 43 is a view showing a manufacturing process of the connection unit(view No. 19).

FIG. 44 is a view showing a manufacturing process of the connection unit(view No. 20).

FIG. 45 is a view showing a manufacturing process of the connection unit(view No. 21).

FIG. 46 is a view showing a manufacturing process of the connection unit(view No. 22).

FIG. 47 is a view showing a manufacturing process of the connection unit(view No. 23).

FIG. 48 is a view showing a manufacturing process of the connection unit(view No. 24).

FIG. 49 is a perspective view explaining an internal structure of theconnection unit.

FIG. 50 is a view showing a manufacturing process of a stepped structurein the connection unit (view No. 1).

FIG. 51 is a view showing a manufacturing process of the steppedstructure in the connection unit (view No. 2).

FIG. 52 is a view showing a manufacturing process of the steppedstructure in the connection unit (view No. 3).

FIG. 53 is a view showing a manufacturing process of the steppedstructure in the connection unit (view No. 4).

FIG. 54 is a view showing a manufacturing process of the steppedstructure in the connection unit (view No. 5).

FIG. 55 is a view showing a manufacturing process of the steppedstructure in the connection unit (view No. 6).

FIG. 56 is a view showing a manufacturing process of the steppedstructure in the connection unit (view No. 7).

FIG. 57 is a view showing a manufacturing process of the steppedstructure in the connection unit (view No. 8).

FIG. 58 is a view showing a manufacturing process of the steppedstructure in the connection unit (view No. 9).

FIG. 59 is a view showing a manufacturing process of the steppedstructure in the connection unit (view No. 10).

FIG. 60 is a view showing a manufacturing process of the steppedstructure in the connection unit (view No. 11).

FIG. 61 is a view showing a manufacturing process of the steppedstructure in the connection unit (view No. 12).

FIG. 62 is a view showing a manufacturing process of the steppedstructure in the connection unit (view No. 13).

FIG. 63 is a view showing a manufacturing process of the steppedstructure in the connection unit (view No. 14).

FIG. 64 is a view showing a manufacturing process of the steppedstructure in the connection unit (view No. 15).

FIG. 65 is a view showing a manufacturing process of the steppedstructure in the connection unit (view No. 16).

FIG. 66 is a view showing a manufacturing process of the steppedstructure in the connection unit (view No. 17).

FIG. 67 is a view showing a manufacturing process of the steppedstructure in the connection unit (view No. 18).

FIG. 68 is a view showing a manufacturing process of the cell array unitand the connection unit (view No. 1).

FIG. 69 is a view showing a manufacturing process of the cell array unitand the connection unit (view No. 2).

FIG. 70 is a view showing a manufacturing process of the cell array unitand the connection unit (view No. 3).

FIG. 71 is a view showing a manufacturing process of the cell array unitand the connection unit (view No. 4).

FIG. 72 is a view showing a manufacturing process of the cell array unitand the connection unit (view No. 5).

FIG. 73 is a view showing a manufacturing process of the cell array unitand the connection unit (view No. 6).

FIG. 74 is a view showing a manufacturing process of the cell array unitand the connection unit (view No. 7).

FIG. 75 is a view showing a manufacturing process of the cell array unitand the connection unit (view No. 8).

FIG. 76 is a view showing a manufacturing process of the cell array unitand the connection unit (view No. 9).

FIG. 77 is a view showing a manufacturing process of the cell array unitand the connection unit (view No. 10).

FIG. 78 is a view showing a manufacturing process of the cell array unitand the connection unit (view No. 11).

FIG. 79 is a view showing a manufacturing process of the cell array unitand the connection unit (view No. 12).

FIG. 80 is a view showing a manufacturing process of the cell array unitand the connection unit (view No. 13).

FIG. 81 is a view showing a manufacturing process of the cell array unitand the connection unit (view No. 14).

FIG. 82 is a view showing a manufacturing process of the cell array unitand the connection unit (view No. 15).

FIG. 83 is a perspective view of external appearance of a connectionunit of a semiconductor memory device according to a first modifiedexample.

FIG. 84 is a perspective view of external appearance of a connectionunit of a semiconductor memory device according to a second modifiedexample.

FIG. 85A is a view for explaining an internal configuration of theconnection unit shown in FIG. 84.

FIG. 85B is a view for explaining the internal configuration of theconnection unit shown in FIG. 84.

FIG. 85C is a view for explaining the internal configuration of theconnection unit shown in FIG. 84.

FIG. 86 is a perspective view of external appearance of a connectionunit of a semiconductor memory device according to a third modifiedexample.

FIG. 87 is a correspondence table of the manufacturing process viewsaccording to FIGS. 10 to 82.

DETAILED DESCRIPTION

A semiconductor memory device according to an embodiment comprises: acell array unit; and a connection unit that is provided adjacently tothe cell array unit and is electrically connected to a peripheralcircuit unit disposed below the cell array unit. The cell array unitincludes: a plurality of word lines that extend in a first direction andare respectively disposed with a certain spacing in a second directionand a third direction, the second direction intersecting the firstdirection, and the third direction being a stacking direction thatintersects the first direction and the second direction; a plurality ofbit lines that extend in the third direction and are respectivelydisposed with a certain spacing in the first direction and the seconddirection; a variable resistance layer that is provided on a sidesurface facing the word line in the bit line and that functions as astorage element at an intersection of the bit line and the word line; aplurality of select gate lines that are provided in a layer upward ofthe plurality of word lines and that function as a control gate forselecting the bit line; and a plurality of global bit lines that areprovided in a layer upward of the plurality of select gate lines andthat are electrically connected to the plurality of bit lines via thecontrol gate. The connection unit includes: a lower wiring line layer inwhich a base unit is formed, the base unit bundling the plurality ofword lines; a middle wiring line layer that is provided on the lowerwiring line layer and in which the plurality of select gate linesextending from the cell array unit are formed; and an upper wiring linelayer that is provided on the middle wiring line layer and in which thesame wiring line layer as the plurality of global bit lines is formed.The lower wiring line layer includes: a first penetrating electrode thatconnects the plurality of word lines and the peripheral circuit unit;and a second penetrating electrode that connects at least one of themiddle wiring line layer and upper wiring line layer and the peripheralcircuit unit.

A method of manufacturing a semiconductor memory device according to anembodiment comprises: (a step for) forming a lower wiring line layer,the lower wiring line layer including a word line stacked structure inwhich a plurality of insulating layers and a plurality of word linelayers are alternately stacked; (a step for) forming a firstthrough-hole in a connection unit of the lower wiring line layer, theconnection unit being connected to a peripheral circuit unit disposeddownwardly of the lower wiring line layer, and the first through-holepenetrating the lower wiring line layer up and down; (a step for)forming a second through-hole in the connection unit, the secondthrough-hole reaching from an upper surface of the lower wiring linelayer to each layer of the plurality of word line layers; (a step for)supplying a via material to the first through-hole and the secondthrough-hole and respectively forming a first penetrating electrode anda second penetrating electrode, the first penetrating electrodeconnecting the plurality of word lines and the peripheral circuit unit,and the second penetrating electrode connecting the wiring line layerformed upwardly of the lower wiring line layer and the peripheralcircuit unit; (a step for,) in a cell array unit that is adjacent in afirst direction to the connection unit of the lower wiring line layer,patterning the word line stacked structure and forming a plurality ofword lines that extend in the first direction, with a certain spacing ina second direction, the second direction intersecting the firstdirection; (a step for) forming a variable resistance layer on a sidesurface of the plurality of word lines, the variable resistance layerfunctioning as a storage element; (a step for) forming between thevariable resistance layers a plurality of bit lines that extend in athird direction, with a certain spacing in the first direction and thesecond direction, the third direction being a stacking direction thatintersects the first direction and the second direction; (a step for)forming a middle wiring line layer upwardly of the lower wiring linelayer, the middle wiring line layer being formed straddling the cellarray unit and the connection unit, and the middle wiring layerincluding a plurality of select gate lines that each function as acontrol gate for selecting the bit line; (a step for) forming an upperwiring line layer upwardly of the middle wiring line layer, the upperwiring line layer including a plurality of global bit lines that areelectrically connected to the plurality of bit lines via the controlgate; and (a step for) connecting at least one of the middle wiring linelayer and upper wiring line layer and the second penetrating electrode.

An embodiment will be described in detail below with reference to thedrawings.

First Embodiment

[Configuration]

FIG. 1 is an overall block diagram of a semiconductor memory deviceaccording to a first embodiment. As will be mentioned in detail at alater stage, a memory cell array 1 has a structure in which a memorycell (MC) including a variable resistance layer is providedthree-dimensionally at an intersection of a word line (WL) extending ina horizontal direction and a bit line (BL) extending in a verticaldirection. Respectively connected to the memory cell array 1 are a wordline decoder (referred to below as “WL decoder 2”), a global bit linedecoder (referred to below as “GBL decoder 3”), and a selector decoder4.

The WL decoder 2 is connected to a plurality of the word lines (WL) inthe memory cell array 1. The GBL decoder 3 is connected to a pluralityof global bit lines (GBL) in the memory cell array 1. The selectordecoder 4 is connected to a plurality of select gate lines (SGL) in thememory cell array 1. The WL decoder 2, the GBL decoder 3, and theselector decoder 4 respectively select the word line, the global bitline, and the select gate line connected to the memory cell which is tobe a target of a read/write/erase, based on address information (a WLaddress, a GBL address, and a selector address) inputted from a higherblock 5.

A power supply 6 generates combinations of voltages corresponding toeach of operations of the read/write/erase (refer to FIG. 7). The powersupply 6 respectively supplies a bias voltage of a selected word line(WL_s) and a bias voltage of an unselected word line (WL_u) to the WLdecoder 2, a bias voltage (GBL_s) of a selected global bit line (GBL_s)and a bias voltage of an unselected global bit line (GBL_u) to the GBLdecoder 3, and a select gate line voltage (SGL_s) to the selectordecoder 4. The present configuration makes it possible to perform theread/write/erase on any memory cell in the memory cell array 1.

FIG. 2 is a perspective view of external appearance of the semiconductormemory device according to the first embodiment. A peripheral circuitlayer 12 and a memory layer 14 are sequentially stacked on a substrate10. Employable in the substrate 10 is, for example, a silicon (Si)substrate. The peripheral circuit layer 12 is a layer includingperipheral circuits such as the WL decoder 2, the GBL decoder 3, theselector decoder 4, and the higher block 5 shown in FIG. 1, and may beformed by a commonly employed semiconductor process.

The memory layer 14 includes a memory cell unit 16 that includes thememory cell array 1 shown in FIG. 1. Provided in a periphery of thememory cell unit 16 is a connection unit (not illustrated in FIG. 2,will be mentioned in detail at a later stage) for achieving electricalconnection with the peripheral circuit layer 12. Blocks that each adoptsaid connection unit and memory cell unit 16 as a unit are disposed in amatrix on the memory layer 14. Moreover, provided in a periphery of aregion where the memory cell units 16 are disposed in a matrix (providedat an edge of the memory layer 14) is an input/output unit 18 of thesemiconductor memory device.

FIG. 3 is a perspective view of external appearance of the memory cellunit 16 in FIG. 2. Provided between two cell array units 20 is aconnection unit 21 for achieving electrical connection with theperipheral circuit layer 12. The memory cell unit 16 is broadly dividedinto three layers in a stacking direction, that is, in order ofcloseness to the peripheral circuit layer 12, a lower wiring line layer30, a middle wiring line layer 31, and an upper wiring line layer 32.Detailed configurations of each layer and each unit will be described indetail by FIG. 4 and later drawings.

Now, in FIG. 3, a first direction which is horizontal to the substrate10 and in which the word line WL extends is referred to as an Xdirection. Moreover, a second direction which is horizontal to thesubstrate 10 and which intersects the X direction is referred to as a Ydirection. Furthermore, a third direction (the stacking direction) whichintersects both of the X direction and the Y direction is referred to asa Z direction. Meanings of these directions are similar also indescriptions of FIG. 4 and later drawings.

As shown in FIG. 3, the lower wiring line layer 30 of the cell arrayunit 20 has stacked therein, via an insulating film 60, a plurality ofthe word lines WL extending in the X direction. The middle wiring linelayer 31 of the cell array unit 20 is provided with a plurality of theselect gate lines SGL extending in the X direction, and said select gatelines SGL extend to the cell array unit 20 on an opposite side via theconnection unit 21. The upper wiring line layer 32 of the cell arrayunit 20 is provided with a plurality of the global bit lines GBLextending in the Y direction.

The lower wiring line layer 30, the middle wiring line layer 31, and theupper wiring line layer 32 are formed also in the connection unit 21,similarly to in the cell array unit 20. Wiring lines of each wiring linelayer are respectively formed by the same materials as wiring lines ofthe cell array unit 20. Formed in the upper wiring line layer 32 of theconnection unit 21 are a first wiring line pattern 101 and a secondwiring line pattern 102, and these wiring line patterns are connected todownward wiring line layers via a third penetrating electrode 97 and afourth penetrating electrode 98. Detailed configurations of the cellarray unit 20 and the connection unit 21 will be mentioned later.

FIG. 4 is a perspective view of external appearance showing part of thecell array unit 20. The plurality of word lines WL extending in the Xdirection are disposed with a certain spacing in each of the Y directionand the Z direction. Respectively provided upwardly of the word lines WL(on an opposite side to the peripheral circuit layer 12) are theplurality of select gate lines SGL extending in the X direction and theplurality of global bit lines GBL extending in the Y direction.

Disposed between the word lines WL with a certain spacing in each of theX direction and the Y direction are the plurality of column shaped bitlines BL extending in the Z direction. Formed on a side surface facingthe word line WL of side surfaces of the bit line BL is a variableresistance layer 40 whose resistance changes by application of avoltage. The variable resistance layer 40 is sandwiched by the bit lineBL and the word line WL at each of intersections of the bit line BL andthe word line WL. The variable resistance layer 40 of said region isapplied with voltages corresponding to each of the operations ofread/write/erase from each of the bit line BL and the word line WL, andthereby functions as the memory cell MC which is a storage element.

The variable resistance layer 40 is formed from a resistance varyingmaterial that undergoes transition between at least two states, that is,a low-resistance state and a high-resistance state. The variableresistance layer 40 in the high-resistance state undergoes transition tothe low-resistance state when a certain voltage or more is applied tothat variable resistance layer 40. The variable resistance layer 40 inthe low-resistance state undergoes transition to the high-resistancestate when a certain current or more is passed through that variableresistance layer 40. Employable as the variable resistance layer 40 is,for example, hafnium oxide (HfO), but alternatively, a thin film layerincluding the likes of TiO₂, ZnMn₂O₄, NiO, AlO, SrZrO₃,Pr_(0.7)Ca_(0.3)MnO₃, and so on, may be appropriately employed.

A channel region 42 is formed at an upper end of the bit line BL. Agateinsulating film 44 is formed on a side surface of the channel region 42.The channel region 42 is configured to contact the select gate line SGLvia said gate insulating film 44. Said region positioned at the upperend of the bit line BL functions as a selection element 41 for selectingthe bit line BL.

FIGS. 5A and 5B are plan views in which the cell array unit 20 of FIG. 4is viewed from the stacking direction (Z direction). FIG. 5A is a topview in which the cell array unit 20 is viewed from above, and FIG. 5Bis a bottom view in which the cell array unit 20 is viewed from below (aperipheral circuit layer 12 side). As shown in FIG. 5B, the plurality ofword lines WL extending in the X direction are alternately bunched by abase portion 120 extending in the Y direction, and form comb toothshaped electrode patterns that face each other. Each of the comb typeelectrode patterns is provided with an identical voltage.

FIG. 6 is a cross-sectional schematic view along a Y-Z planar surface ofthe cell array unit 20, and FIG. 7 is a table showing applied voltagesto the cell array unit 20 during each of the operations ofread/write/erase. In FIG. 7, SGL_s indicates a selected gate line, SGL_uindicates an unselected gate line, GBL_s indicates a selected global bitline, GBL_u indicates an unselected global bit line, WL_s indicates aselected word line, and WL_u indicates an unselected word line.

FIG. 6 shows an example where the memory cell of a region surrounded bythe symbol MC is selected by respectively selecting the one of the combtype electrode patterns for the bottom word line WL and the second fromright bit line BL. At this time, the selected word line WL is appliedwith a bias voltage of the selected word line WL_s. Moreover, the selectgate lines SGL on both sides of the channel region 42 in the upper endof the selected bit line BL are applied with a bias voltage of theselected gate line SGL_s, and the selection element 41 attains an onstate. As a result, the selected bit line BL is applied with a biasvoltage of the selected global bit line GBL_s via the channel region 42.The other select gate lines SGL are applied with a bias voltage of theunselected gate line SGL_u, hence the selection element 41 attains anoff state. As a result, the unselected bit lines BL are not applied withthe bias voltage of the selected global bit line GBL_s.

Next, details of applied voltages during each of the operations will bedescribed with reference to FIG. 7. During a write operation that storesinformation in the memory cell MC, the selected global bit line (GBL_s)is applied with a Write voltage (Vw), and the selected gate line (SGL_s)is applied with a Write select gate voltage (Vg_w). Meanwhile, theselected word line (WL_s) is set unchanged at 0 V. As a result, bothends of the memory cell MC are applied with a bias voltage correspondingto the Write voltage (Vw) and a resistance value of the variableresistance layer 40 changes, whereby write of data is performed. At thistime, the unselected global bit line (GBL_u) and the unselected wordline (WL_u) are applied with a voltage (Vwf) such that a cell voltage ofa half-selected cell is half of a selected cell voltage. In addition,the unselected select gate line (SGL_u) is maintained in a state of 0 V.

Next, during an erase operation that erases information of the memorycell MC, it is taken into account that a bipolar operation (transitionfrom the high-resistance state to the low-resistance state andtransition from the low-resistance state to the high-resistance statebeing made by applied voltages of different polarity) is performed bythe variable resistance layer 40. That is, the selected global bit line(GBL_s) is applied with an offset voltage Vof (for example, about 1 V),and the selected gate line (SGL_s) is applied with an Erase select gatevoltage (Vg_e). Meanwhile, the selected word line (WL_s) is applied witha value of the offset voltage Vof (approximately about 1 V) added to anErase voltage (Ves). As a result, the selected memory cell MC is appliedwith a bias voltage corresponding to the Erase voltage (Ves) and theresistance value of the variable resistance layer 40 changes, wherebyerase of data is performed. At this time, the unselected global bit line(GBL_u) and the unselected word line (WL_u) are applied with a voltageof Vof added to a voltage (Vef) such that the cell voltage of thehalf-selected cell is half of the selected cell voltage. In addition,the unselected select gate line (SGL_u) is maintained in a state of 0 V.

Now, the reason why the offset voltage Vof is added to the selectedglobal bit line GBL_s and the word line WL is because in terms ofcharacteristics of the selection element 41, setting a potential of theselected global bit line (GBL_s) to a value about 1 V higher than theunselected select gate line (SGL_u) makes it possible to substantiallyreduce a leak current to an unselected cell. Employing as a meansthereof a method that inflates an overall voltage of the selected globalbit line GBL_s and the word line WL as in the present embodiment makesit unnecessary to provide a negative voltage circuit, whereby areduction in circuit area can be achieved.

Next, during a read operation that reads information of the memory cellMC, the selected global bit line (GBL_s) is applied with a voltage ofthe offset voltage (Vo) added to a Read voltage (Vr), and the selectedword line (WL_s) is applied with the offset voltage (Vo). In this state,a Read select gate voltage (Vg_r, 0) applied to the selected gate line(SGL_s) is controlled to perform the read. At this time, the unselectedglobal bit line (GBL_u) and the unselected word line (WL_u) are with avoltage of the offset voltage (Vo) added to the Read voltage (Vr). Inaddition, the unselected select gate line (SGL_u) is maintained in astate of 0 V.

Now, the reason why the offset voltage Vo is added to the selectedglobal bit line GBL_s and the word line WL will be described. Normally,immediately after the write operation or the erase operation has beenperformed on the memory cell MC, the read operation of said memory cellMC is performed, and it is confirmed whether a desired resistance valuehas been achieved (verify operation). At this time, when the resistancevalue of said memory cell MC differs from a range of the desiredresistance value, an additional write operation or erase operation isperformed. Therefore, when a large voltage difference exists betweenbias conditions in the write operation or the erase operation and biasconditions in the read operation, there is a possibility that anincrease in power consumption or a delay in operation time occurs. It isparticularly undesirable that an operation accompanied by a rapidvoltage change is performed by a node having a large parasiticcapacitance.

In the present embodiment, parasitic capacitance of the global bit lineGBL is largest, hence it is preferable to set such that the potential ofthe global bit line GBL does not change greatly between the readoperation and other operations (the write operation or the eraseoperation). Furthermore, there are more unselected global bit lines(GBL_u) than selected global bit lines (GBL_s), hence it is preferableto set such that the potential of the unselected global bit line doesnot change greatly between the read operation and other operations (thewrite operation or the erase operation). Therefore, it is preferable toset the offset voltage Vo such that Vwf and Vr+Vo are substantiallyequal during write and Vef+Vof and Vr+Vo are substantially equal duringerase.

In each of the operations of write/erase/read, only one selected wordline (WL_s) is selected per memory cell array of one block. In contrast,a plurality of selected global bit lines (GBL_s) may be simultaneouslyselected. As a result, the number of bit lines capable of simultaneouslyperforming write/erase/read increases, hence making it possible toachieve a reduction in operation time.

FIG. 8 is a perspective view of external appearance of the connectionunit 21, and illustration of an inter-layer insulating film is omitted.In the lower wiring line layer 30 of the connection unit 21, a stackedstructure of the word lines WL extending from the cell array unit 20 isbunched by the base portion 120 (refer to FIG. 9) extending in the Ydirection. Layers of word lines WL are formed from, for example, 16layers, via the inter-layer insulating film between the layers. Eachlayer of word lines WL is electrically connected to the peripheralcircuit layer 12 positioned downwardly of the cell array unit 20 and theconnection unit 21, by a first penetrating electrode 50 formed in thelower wiring line layer 30.

The first penetrating electrodes 50 of the present embodiment aredisposed eight at a time aligned in two columns in the Y direction, andare respectively connected to 16 different layers of word lines WL. Thefirst penetrating electrodes 50 each include two columnar portions. Afirst columnar portion 111 positioned on an outer side is connected tothe word line WL, and a second columnar portion 110 positioned on aninner side penetrates the entire lower wiring line layer 30 to beelectrically connected to the peripheral circuit layer 12. The firstcolumnar portion 111 and the second columnar portion 110 are connectedby a bridging portion 112 at an upper surface of the lower wiring linelayer 30. A detailed configuration of the first penetrating electrode 50is as shown in the manufacturing process view of FIG. 67.

Moreover, formed in the lower wiring line layer 30 is a secondpenetrating electrode 52 that electrically connects wiring line layers(the middle wiring line layer 31 and the upper wiring line layer 32)positioned upwardly of the lower wiring line layer 30, and theperipheral circuit layer 12. The second penetrating electrode 52 ispositioned on an outer side of a region where the first penetratingelectrode 50 is formed, and penetrates the lower wiring line layer 30from an upper surface to a lower surface. A detailed configuration ofthe second penetrating electrode 52 is also as shown in themanufacturing process view of FIG. 67.

Provided in the middle wiring line layer 31 positioned on the lowerwiring line layer 30 are the plurality of select gate lines SGLextending from the cell array unit 20. In principle, the select gatelines SGL are disposed in parallel so as to extend in the X direction,but the select gate line SGL positioned at a connection portion with thesecond penetrating electrode 52 alone has a partly divided shape.

Provided in the upper wiring line layer 32 positioned on the middlewiring line layer 31 are the first wiring line pattern 101 and thesecond wiring line pattern 102 formed in the same wiring line layer asthe global bit line GBL. The first wiring line pattern 101 extends inthe Y direction, has its one end connected to the fourth from end selectgate line SGL via a third penetrating electrode 97, and has its otherend connected to the second penetrating electrode 52 in the lower wiringline layer 30 via a fourth penetrating electrode 98. The thirdpenetrating electrode 97 that connects the first wiring line pattern 101and the select gate line SGL is formed by the same material as theselect gate line SGL and integrally with the select gate line SGL, in ashape where part of the select gate line SGL protrudes upwardly. On theother hand, the fourth penetrating electrode 98 that connects the firstwiring line pattern 101 and the second penetrating electrode 52 isformed by a different material from the select gate line SGL and thethird penetrating electrode 97.

Due to the above-described configuration, the fourth from end selectgate line SGL is electrically connected to the peripheral circuit layer12 positioned downwardly of the connection unit 21, via the thirdpenetrating electrode 97, the first wiring line pattern 101, the fourthpenetrating electrode 98, and the second penetrating electrode 52.Moreover, the second wiring line pattern 102 is a wiring line patternformed so as to bypass the connection portion of the first wiring linepattern 101 and the fourth penetrating electrode 98, and its both endsare each connected to the select gate line SGL via the third penetratingelectrode 97. As a result, the fellow select gate lines SGL divided at aplace of formation of the fourth penetrating electrode 98 areelectrically connected via the second wiring line pattern 102 in theupper wiring line layer 32.

FIG. 9 is a planar schematic view of the lower wiring line layer 30including a plurality of the cell array units 20 and the connectionunits 21. The word lines WL are bunched by the base portion 120 and formcomb tooth shaped electrode patterns that face each other in the Xdirection. Of the penetrating electrodes formed in the lower wiring linelayer 30, the first penetrating electrode 50 that connects the word lineWL and the peripheral circuit layer 12 is provided in a region wherefellow teeth of the comb teeth face each other in the X direction. Insaid region, the word lines WL extending from the base portion 120 arenot formed, and interference with said word lines WL can be avoided.

Moreover, of the penetrating electrodes formed in the lower wiring linelayer 30, the second penetrating electrode 52 that connects wiring linelayers upward of the lower wiring line layer 30 and the peripheralcircuit layer 12 is provided between fellow comb tooth shaped wiringline patterns adjacent in the Y direction. In said region, neither ofthe base portion 120 of the word lines WL nor the word lines WLextending from the base portion 120 are formed, and interference withthese layers can be avoided.

In a conventional publicly-known semiconductor memory device, theperipheral circuit layer 12 shown in FIG. 2 is formed not on a sidewhere the stacked structure of the word lines WL is formed (a lowerwiring line layer 30 side of the present embodiment), but on a sidewhere the global bit lines GBL are formed (an upper wiring line layer 32side of the present embodiment). Therefore, in order to electricallyconnect the word line WL and the peripheral circuit layer 12, contactsare formed avoiding the select gate line SGL positioned between them, inthe connection unit 21. As a result, space of the connection unit 21increases, and it sometimes ends up becoming difficult to achieve anincreased integration level of the semiconductor memory device.

In contrast, in the semiconductor memory device according to the presentembodiment, the peripheral circuit layer 12 is provided on the sidewhere the stacked structure of the word lines WL is formed (the lowerwiring line layer 30 side). Therefore, a contact (first penetratingelectrode 50) for electrically connecting the word line WL and theperipheral circuit layer 12 is directly connected to the peripheralcircuit layer 12, without passing through the middle wiring line layer31 where the select gate lines SGL are present. Therefore, there is noneed to form the contact avoiding the select gate line SGL asconventionally, and increase in space of the connection unit 21 can besubstantially suppressed.

On the other hand, the select gate line SGL is connected to theperipheral circuit layer 12 by penetrating the lower wiring line layer30 by a contact (second penetrating electrode 52) formed at a positionnot overlapping the word line WL. However, the select gate line SGL isshared by a plurality of cell array units 20 aligned in the direction ofextension of the select gate line SGL (X direction), hence there is noneed to form contacts corresponding to all of the select gate lines SGLin one connection unit 21. For example, as in the present embodiment, itis possible to adopt a configuration in which only one select gate lineSGL-dedicated contact is formed per one connection unit 21, and theother select gate lines SGL are electrically connected to the peripheralcircuit layer 12 in the other connection units 21. As a result, thenumber of select gate line SGL-dedicated contacts formed in oneconnection unit 21 becomes substantially fewer compared to the number ofword line WL-dedicated contacts formed in the same connection unit 21,and the influence exerted on space increase of the connection unit 21 isslight.

Due to the above configuration, the semiconductor memory deviceaccording to the present embodiment is enabled to achieveminiaturization and an increased integration level of the device bysuppressing space increase of the connection unit 21. Note that asexplained by FIG. 9, in terms of disposition, the first penetratingelectrode 50 and the second penetrating electrode 52 are preferablyprovided in a gap of the comb tooth shaped wiring line patterns of theword lines WL (a region where fellow teeth face each other). As aresult, space increase of the connection unit 21 accompanying formationof the first penetrating electrode 50 and the second penetratingelectrode 52 can be suppressed.

[Method of Manufacturing]

Next, a method of manufacturing the semiconductor memory deviceaccording to the first embodiment will be described. The cell array unit20 and the connection unit 21 shown in FIG. 3 are formed by commonmanufacturing processes, but FIGS. 10 to 24 show only manufacturingprocesses of the cell array unit 20, and FIGS. 25 to 48 show onlymanufacturing processes of the connection unit 21. FIGS. 50 to 67 areviews showing manufacturing processes of a stepped structure (laterdescribed) in the lower wiring line layer 30 of the connection unit 21.FIGS. 68 to 82 are views showing manufacturing processes of both of thecell array unit 20 and the connection unit 21. A correspondencerelationship of each of the process drawings is as in the table shown inFIG. 87.

First, manufacturing processes of the cell array unit 20 will bedescribed with reference to FIGS. 10 to 24. As shown in FIG. 10, theinsulating layers 60 and layers which are to be the word lines (referredto below as “WL layer 61”) are stacked alternately, and a word linestacked structure 62 which is to be part of the lower wiring line layer30 is formed. Employable in the insulating layer 60 is, for example,SiO₂, and a film thickness of the insulating layer 60 can be set to, forexample, 20 nm in a lowermost portion, 13 nm in an uppermost portion,and 7 nm in an inter-layer portion. Employable in the WL layer 61 is,for example, TiN, and a film thickness of the WL layer 61 can be set to,for example, 10 nm.

Next, as shown in FIG. 11, an etching mask 63 of the word line stackedstructure 62 is formed. A pattern of the word lines WL of the cell arrayunit 20 is, for example, a striped shape of a line width of 34 nm andspace of 42 nm (a half pitch of 38 nm), and can be formed by ordinaryphotolithography technology and RIE (Reactive Ion Etching) technology.

Next, as shown in FIG. 12, the mask formed in FIG. 11 is employed tobatch process the word line stacked structure 62 by RIE technology.Following this, as shown in FIG. 13, a layer 64, which consists of aresistance varying material, is formed on a side surface of the nowstriped-shaped word line stacked structure 62. This layer 64 correspondsto the variable resistance layer 40 in FIG. 4, employs, for example,HfOx as its material, and can be formed with a thickness of, forexample, 4 nm. Formation of the layer 64 can be performed by, forexample, an ALD (Atomic Layer Deposition) method. Note that the layer 64is formed also in a trench bottom portion and upper portion of thepatterned word line stacked structure 62, but electrical connection isnot formed in these portions, hence they may be disregarded (notillustrated in FIG. 13).

Next, as shown in FIG. 14, a bit line film 65 is formed in an entiretrench portion of the word line stacked structure 62, and by polishingby a CMP (Chemical Mechanical Polishing) method, the bit line film 65 isleft only inside the trench. The bit line film 65 corresponds to the bitline BL in FIG. 4, and can be formed employing, for example, n+ typepolycrystalline silicon as its material.

Next, as shown in FIG. 15, photolithography technology and RIEtechnology are employed to pattern the bit line film 65 into a pillarshape. The present patterning process can be performed by conditionsthat, for example, line width and adjacency spacing are bothapproximately 24 nm. As a result of the present process, the bit line BLis completed. Subsequently, a trench between adjacent bit lines BL isfilled with an inter-layer insulating layer (said process is notillustrated), and a surface is planarized by a CMP method.

Next, as shown in FIG. 16, an n+ type silicon layer 66, a p− typesilicon layer 67, and an n+ type silicon layer 68 are sequentiallyformed. The p− type silicon layer 67 corresponds to the channel region42 in FIG. 4. The n+ type silicon layers 66 and 68 have a dopantconcentration of, for example, 1×10²⁰ cm⁻³, and their film thickness is,for example, 40 nm. The p− type silicon layer 67 has a dopantconcentration of, for example, 1×10¹⁸ cm⁻³and its film thickness is, forexample, 120 nm. After the silicon layers 66 to 68 are stacked,annealing is performed by conditions of, for example, approximately 750°C. and 60 seconds, and the silicon layers 66 to 68 are crystallized.

Next, as shown in FIG. 17, the silicon layers 66 to 68 are patterned byphotolithography technology and RIE technology. As a result, a stripeshaped pattern extending in the Y direction is formed. A line width andspace of the silicon layer pattern can be set to, for example, 24 nm.Subsequently, an inter-layer insulating layer is formed on an entiresurface, and then an upper surface of the n+ type silicon layer 68 isexposed by polishing by the likes of a CMP method. As a result, a trenchportion occurring due to the process of FIG. 17 is filled by aninter-layer insulating film (said process is not illustrated).

Next, as shown in FIG. 18, photolithography technology and RIEtechnology are employed to pattern the silicon layers 66 to 68. As aresult, a stripe shaped pattern extending in the X direction is formed,and combined with the process of FIG. 17, the silicon layers 66 to 68are patterned in a matrix. As a result of the present process, thesilicon layers 66 to 68 are divided into the channel regions 42 for eachof the selection elements 41 shown in FIG. 4, and are disposed directlyabove the bit line BL. The present patterning process can be performedby conditions of, for example, a line width of 34 nm and a space of 42nm (a half pitch of 38 nm).

Next, as shown in FIG. 19, an insulating film 70 is formed on an entiresurface of the silicon layers 66 to 68, and then etching is performed,and the insulating film 70 is configured to remain only in a trenchbottom portion formed by the silicon layers 66 to 68. Employable in theinsulating film 70 is, for example a silicon oxide film, and a thicknessof the insulating film 70 can be set to, for example, 30 nm.

Next, as shown in FIG. 20, an insulating film 71 is formed on sidesurfaces of the silicon layers 66 to 68. The insulating film 71corresponds to the gate insulating film 44 shown in FIG. 4, and its filmthickness can be set to, for example, 5 nm. The insulating film 71 isformed also in the trench bottom portion of the silicon layers 66 to 68,but the thickness of the previously mentioned insulating film 70 onlychanges slightly, hence indication thereof in the present drawing isomitted. Moreover, the insulating film 71 formed on the upper surface ofthe n+ type silicon layer 68 is removed by a later CMP process (FIG.22), hence similarly, indication thereof in the present drawing isomitted.

Next, as shown in FIG. 21, a conductive film 72 is filled inside thetrench of the silicon layers 66 to 68. The conductive film 72corresponds to the select gate line SGL shown in FIG. 4, and may employ,for example, an n+ type polycrystalline silicon layer, but alternativelymay employ p+ type polycrystalline silicon, TiN, TiSi, WS, and so on.After filling the conductive film 72, an upper surface of the conductivefilm 72 is etched, and a film thickness of the conductive film 72 is setto, for example, 140 nm. Due to the present process, a bottom surface ofthe select gate line SGL is set lower than a lower surface of the p−type silicon layer 67, and an upper surface of the select gate line SGLis set higher than an upper surface of the p− type silicon layer 67.

Next, as shown in FIG. 22, an insulating film 73 is formed on an entiresurface. Employable in the insulating film 73 is, for example, a siliconoxide film. Subsequently, the insulating film 73 is polished by, forexample, a CMP method, and the insulating film 73 is configured toremain only inside the trench formed by the n+ type silicon layer 68. Atthis time, the upper surface of the n+ type silicon layer 68 is alsoexposed.

Next, as shown in FIG. 23, a global bit line film 75 is formed. Theglobal bit line film 75 corresponds to the global bit line GBL shown inFIG. 4. Employable as a material of the global bit line film 75 is, forexample, a stacked film of a TiN film acting as a barrier metal andtungsten (W) acting as a wiring line main body.

Next, as shown in FIG. 24, the global bit line film 75 is patterned byphotolithography technology and RIE technology, and a stripe shapedpattern extending in the Y direction is formed on the silicon layers 66to 68 which are to be the selection element 41. A line width and a spaceof the global bit line GBL may be set to, for example, 24 nm, and a filmthickness of the global bit line GBL may be set to, for example, 150 nm.A sheet resistance of the global bit line GBL is, for example, 1.5 Ω/sq.Subsequently, an inter-layer insulating film is formed on an entiresurface and polishing is performed by the likes of a CMP method, wherebya trench portion occurring due to formation of the global bit line GBLis filled with the inter-layer insulating film (the present process isnot illustrated). As a result, the cell array unit 20 is completed.

Following this, manufacturing processes of the connection unit 21 willbe described with reference to FIGS. 25 to 67. First, as shown in FIG.25, the insulating layers 60 and the WL layers 61 are stackedalternately, and the word line stacked structure 62 is formed. Thepresent process is similar to that described in FIG. 10.

Next, as shown in FIG. 26, an etching-dedicated first mask 80 is formedon an upper surface. Employable in the first mask 80 is, for example,SiN having a film thickness of 100 nm. Next, as shown in FIG. 27,photolithography technology and RIE technology are employed to processthe first mask 80 and form a first pattern 81. At this time, an openingof the first pattern 81 is configured to be formed at positionscorresponding to the first penetrating electrode 50 and the secondpenetrating electrode 52 shown in FIG. 8. Note that attention is paidsuch that RIE stops at a stage where the first mask has been penetratedand an upper surface of the word line stacked structure 62 is notremoved.

Next, as shown in FIG. 28, an etching-dedicated second mask 82 is formedoverlapping the first mask 80. Employable in the second mask 82 is, forexample, a coating type carbon system film having a film thickness of100 nm. The second mask 82 extends in the Y direction and is formed soas to cover part of the opening of the first mask 80 (a position wherethe first columnar portion 111 of the first penetrating electrode 50shown in FIG. 8 is formed).

Next, as shown in FIG. 29, the word line stacked structure 62 atportions thereof not covered by either of the first mask 80 and thesecond mask 82 is removed to a lowermost layer using RIE technology, anda first through-hole 83 is formed. The first through-hole 83 formed inthe present process is later to be a connection portion to theperipheral circuit layer 12, hence the above-described RIE may beperformed to a depth reaching the peripheral circuit layer 12. Thesecond penetrating electrode 52 and the second columnar portion 110 ofthe first penetrating electrode 50 shown in FIG. 8 correspond to thefirst through-hole 83 formed in the present process.

Next, as shown in FIG. 30, the second mask 82 is etched isotropically.Due to the present process, the second mask 82 is shrunk (reduced) by,for example, 10 nm in the X direction (refer to symbol 85). Next, asshown in FIG. 31, a first sidewall protecting film 86 is formeduniformly on an entire surface. As a result, a side surface of the firstthrough-hole 83 formed in FIG. 29 and a side surface of the second mask82 shrunk by the process of FIG. 30 are covered by the first sidewallprotecting film 86. Employable in the first sidewall protecting film 86is, for example, SiN having a film thickness of 10 nm.

Next, as shown in FIG. 32, the second mask 82 is removed. Subsequently,a region which is not covered by either of the first mask 80 or thefirst sidewall protecting film 86 and which was covered by the secondmask 82 (refer to symbol 87) is removed using RIE technology until anuppermost layer word line WL film is reached. Removed by etching in thepresent process is part of a region where the first columnar portion 111connected to the word line WL of the first penetrating electrode 52shown in FIG. 8 is formed.

Next, as shown in FIG. 33, an etching-dedicated third mask 88 is formedusing photolithography technology and RIE technology. The third mask 88is formed extending in the Y direction so as to cover one side of theconnection unit 21. Subsequently, as shown in FIG. 34, RIE is performedon the upper surface of the word line stacked structure 62 on a sidethereof not covered by the third mask 88, and one each of the uppermostlayer WL layer 61 and the uppermost layer insulating layer 60 areremoved. Subsequently, as shown in FIG. 35, the third mask 88 isremoved. Due to the above processes, a height of the word line stackedstructure 62 on the side thereof etched in FIG. 34 becomes lower by anamount of a one group portion (a total of a two layer portion) of the WLlayer 61 and the insulating layer 60, compared to the word line stackedstructure 62 on the side thereof which was covered by the third mask 88.

Now, processes from FIG. 35 to FIG. 36 will be described using FIGS. 50to 67. FIG. 50 is a perspective view of an identical stage to that ofFIG. 35, and in order to render processes more easily seen, it isconfigured as a drawing looking from a viewpoint on a 180° opposite sideto that of FIG. 35.

Next, as shown in FIG. 51, an etching-dedicated fourth mask 90 is formedby photolithography technology. Employable in the fourth mask 90 is, forexample, a resist. FIG. 52 is a perspective view of an identical stageto that of FIG. 51, and in order to render processes more easily seen,visibly displays only a portion (referred to below as “WL steppedportion 91”) later to be the stepped structure of the word line stackedstructure 62, and the fourth mask 90 (the same applies below to FIGS. 53to 67). At the stage of FIG. 52, only the two WL stepped portions 91positioned most to a front side are in a state of not being covered bythe fourth mask 90.

Next, as shown in FIG. 53, a first RIE process is performed, and twolayers each of each of the WL layers 61 and the insulating layers 60 (atotal of four layers) in WL stepped portions 91 a and 91 b not coveredby the fourth mask 90, are removed by RIE. As a result, heights of theWL stepped portions 91 a and 91 b each become lower by an amount of afour layer portion compared to before etching. Moreover, since the WLstepped portion 91 on one side only was etched beforehand by a two layerportion in FIG. 34, the height of the WL stepped portion 91 b is lowerby an amount of a further two layer portion compared to the WL steppedportion 91 a.

Next, a first shrink process is performed, and an upper portion andfront portion (WL stepped portions 91 a and 91 b side) of the fourthmask 90 is etched back by an amount of a one terrace pitch portion (forexample, approximately 152 nm). As a result, WL stepped portions 91 cand 91 d are newly exposed on an outer side of the fourth mask 90 andbecome a target of etching in a following RIE process.

Hereafter, the RIE process and the shrink process are repeatedlyperformed, similarly to as described by FIGS. 53 to 54. In a second RIEprocess shown in FIG. 55, four layers each of the WL stepped portions 91a to 91 d not covered by the fourth mask 90 are removed by RIE. In asecond shrink process shown in FIG. 56, WL stepped portions 91 e and 91f are newly exposed on an outer side of the fourth mask 90.

In a third RIE process shown in FIG. 57, four layers each of the WLstepped portions 91 a to 91 f not covered by the fourth mask 90 areremoved by RIE. In a third shrink process shown in FIG. 58, WL steppedportions 91 g and 91 h are newly exposed on an outer side of the fourthmask 90. In a fourth RIE process shown in FIG. 59, four layers each ofthe WL stepped portions 91 a to 91 h not covered by the fourth mask 90are removed by RIE. In a fourth shrink process shown in FIG. 60, WLstepped portions 91 i and 91 j are newly exposed on an outer side of thefourth mask 90.

In a fifth RIE process shown in FIG. 61, four layers each of the WLstepped portions 91 a to 91 j not covered by the fourth mask 90 areremoved by RIE. In a fifth shrink process shown in FIG. 62, WL steppedportions 91 k and 91 l are newly exposed on an outer side of the fourthmask 90. In a sixth RIE process shown in FIG. 63, four layers each ofthe WL stepped portions 91 a to 91 l not covered by the fourth mask 90are removed by RIE. In a sixth shrink process shown in FIG. 64, WLstepped portions 91 m and 91 n are newly exposed on an outer side of thefourth mask 90.

In a seventh RIE process shown in FIG. 65, four layers each of the WLstepped portions 91 a to 91 n not covered by the fourth mask 90 areremoved by RIE. Subsequently, as shown in FIG. 66, residual fourth mask90 is removed, and remaining WL stepped portions 91 o and 91 p areexposed.

In FIG. 66, the WL stepped portion 91 is configured from two columns ofstepped portions extending in the Y direction. Fellow stepped portionsadjacent in the X direction have heights that differ by two layerportions at a time, and fellow stepped portions (within the same column)adjacent in the Y direction have heights that differ by four layerportions at a time. As a result, the 16 WL stepped portions 91 a to 91 pall have heights that differ, and have a configuration in whichdifferent WL layers 61 are exposed on their upper surfaces.

Next, as shown in FIG. 67, a pattern of the penetrating electrode isformed in the opening of the lower wiring line layer 30, whereby thefirst penetrating electrode 50 and the second penetrating electrode 52are formed. The first penetrating electrode 50 includes the firstcolumnar portion 111 connected to the WL layer 61 and the secondcolumnar portion 110 connected to the peripheral circuit layer 12, andthe first columnar portion 111 and second columnar portion 110 areconnected to each other by the bridging portion 112 at the upper surfaceof the lower wiring line layer 30. The second penetrating electrode 52is, for example, a plate-like electrode having a certain width in the Xdirection, and electrically connects wiring line layers positionedupwardly of the lower wiring line layer 30 and the peripheral circuitlayer 12 positioned downwardly of the lower wiring line layer 30.

Description of the manufacturing processes of the connection unit willbe continued returning again to FIG. 36. FIG. 36 is a perspective viewof an identical stage to that of FIG. 66, and a second through-hole 87from an upper surface of the WL stacked structure 62 to an upper surfaceof the WL stepped portion 91 is formed. In a midway process to finishingformation processes of the WL stepped portion 91, a thinly protrudingregion of the first sidewall protecting film 86 (an intermediate region122 separating the two openings for the first penetrating electrodes 50adjacent in the X direction) is partially removed by etching.

Next, as shown in FIG. 37, a second sidewall protecting film 95 isformed uniformly on an entire surface. Employable in the second sidewallprotecting film 95 is, for example, SiN having a film thickness of 10nm. After formation of the second sidewall protecting film 95, etchingis performed, and the second sidewall protecting film 95 present on abottom surface and an upper surface of the opening is removed.

Next, as shown in FIG. 38, a via material 94 is filled in the opening,and an upper portion is planarized by CMP. Due to the present process,the first penetrating electrode 50 and the second penetrating electrode52 shown in FIG. 67 are formed. Employable in the via material 94 is,for example, tungsten (W). In said process, the via material 94 issupplied to the first through-hole 83, the second through-hole 87, andthe intermediate region 122 between the first through-hole 83 and thesecond through-hole 87. This makes it possible for the bridging portion112 formed in the intermediate region 122, as well as the secondcolumnar portion 110 formed in the first through-hole 83 and the firstcolumnar portion 111 formed in the second through-hole 87, to besimultaneously formed during formation of the first penetratingelectrode 50 (refer to FIG. 67). As a result, the manufacturing processcan be made more efficient.

Now, as a result of forming the first sidewall protecting film 86 on theside surface of the shrunk second mask 82 as described in FIGS. 29 to30, in a subsequent process, the intermediate region 122 is configuredto cover a WL stacked structure film of a shrink width by the firstsidewall protecting film 86 and the second sidewall protecting film 95.Sometimes, performing an ordinary sidewall protecting film processwithout shrinking the second mask 82 results in a structure where thefirst columnar portion 111 and the second columnar portion 110 in thefirst penetrating electrode 50 are partitioned only by a thickness ofthe sidewall protecting film, and a process margin cannot besufficiently obtained in a processing process typified by an etchingprocess. However, adding the WL stacked structure film of the shrinkwidth makes it possible for a process margin to be sufficiently secured,and enables insulation properties of said region to be raised andreliability of the semiconductor memory device to be improved.

Next, as shown in FIG. 39, the word line stacked structure 62 is batchprocessed by RIE technology. The present process corresponds to theprocess of FIG. 12 in the cell array unit 20. Next, as shown in FIG. 40,a layer 64 of a resistance varying material configured from, forexample, HfOx having a film thickness of 4 nm is deposited uniformlyemploying, for example, an ALD method. The present process correspondsto the process of FIG. 13 in the cell array unit 20.

Next, as shown in FIG. 41, a bit line film 65 is formed in an entiretrench portion formed in FIG. 39, and by polishing by a CMP method, thebit line film 65 is left only inside the trench. This processcorresponds to the process of FIG. 14 in the cell array unit 20. Next,as shown in FIG. 42, photolithography technology and RIE technology areemployed to pattern the bit line film 65 into a pillar shape. In theconnection unit 21 of the present embodiment, there is no need for thebit line BL to be formed, hence in FIG. 42, the bit line film 65 iscompletely removed. However, even supposing a part of the bit linematerial remains, there is no process for achieving electricalconnection with said place later, hence there is no particular problem.The process of FIG. 42 corresponds to the process of FIG. 15 in the cellarray unit 20. Note that in the cell array unit 20, formation processesof the silicon layers 66 to 68 (refer to FIGS. 16 to 19) are thenperformed, but in the connection unit 21, said silicon layers getcompletely removed by etching, hence a description of said processeswill be omitted.

Next, as shown in FIG. 43, a plurality of conductive films 72 extendingin parallel in the X direction are formed upwardly of the lower wiringline layer 30. Formation of the conductive film 72 can be performed byfilling the conductive film 72 in a trench portion formed in aninter-layer insulating film (not illustrated) in the formation processesof the silicon layers 66 to 68. The conductive film 72 corresponds tothe select gate line SGL shown in FIGS. 3 and 4, and is formed from anidentical material (for example, an n+ type polycrystalline siliconlayer) to that of the conductive film 72 filled in FIG. 21. In FIG. 43,the conductive film 72 is divided in a region upward of the secondpenetrating electrode 52 of the lower wiring line layer 30. In a laterprocess, a penetrating electrode for connecting the upper wiring linelayer 32 and the second penetrating electrode 52 is formed in saidregion.

Next, as shown in FIG. 44, an etching-dedicated fifth mask 96 is formedin a region of the select gate line SGL where connection is to be madeto the upper wiring line layer 32. In the present embodiment, the fifthmask 96 is respectively formed on the fourth from front side select gateline SGL and the second from rear side select gate line SGL. The fifthmask 96 acts in a self-aligning manner with a pattern of the select gateline SGL, hence can be made broader than a width of the select gate lineSGL (need only be in a range that does not overlap the adjacent selectgate line SGL). This makes it possible to relax constraint conditionsduring lithography.

Next, as shown in FIG. 45, the other select gate lines SGL are etchedback, leaving a connection region of the select gate line SGL and theupper wiring line layer 32 covered by the fifth mask 96. Next, as shownin FIG. 46, the fifth mask 96 is removed, and then formation of aninter-layer insulating film and planarization by a CMP method areperformed (indication of the inter-layer insulating film is omitted inFIG. 46). The present process corresponds to the processes of FIGS. 21and 22 in the cell array unit 20. Due to the present process, a regionon the select gate line SGL that was covered by the fifth mask 96attains an upwardly protruding shape. Said protruding shaped regionbecomes a third penetrating electrode 97 that connects the select gateline SGL (middle wiring line layer 31) and the upper wiring line layer32. Due to the above-mentioned processes, the third penetratingelectrode 97 is formed by an identical material to the select gate lineSGL and integrally with the select gate line SGL.

Next, as shown in FIG. 47, photolithography technology and RIEtechnology are employed to provide an opening in a region positioned onthe second penetrating electrode 52 of the lower wiring line layer 30,of the inter-layer insulating layer, and a via material (for example,tungsten (W)) is filled in said opening. Said via material becomes afourth penetrating electrode 98 that connects the upper wiring linelayer 32 and the second penetrating electrode 52. The fourth penetratingelectrode 98 is normally formed by a different material from that of theselect gate line SGL. As a result, although the third penetratingelectrode 97 and the fourth penetrating electrode 98 are the same inthat both are electrically connected to the upper wiring line layer 32,they are formed by different materials from each other.

Next, as shown in FIG. 48, ordinary photolithography technology and RIEtechnology are employed to form a wiring line pattern of the upperwiring line layer 32. The present process corresponds to the process ofFIG. 24 in the cell array unit 20. In the present embodiment, the firstwiring line pattern 101 extending in the Y direction and the secondwiring line pattern 102 bypassing the first wiring line pattern 101 areformed using the same global bit line film 75 as in the cell array unit20. The first wiring line pattern 101 has its one end connected to thefourth from front side select gate line SGL via the third penetratingelectrode 97, and has its other end connected to the second penetratingelectrode 52 of the lower wiring line layer 30 via the fourthpenetrating electrode 98. The second wiring line pattern 102 has itsboth ends each connected to the second from rear side select gate lineSGL via the third penetrating electrode 97.

After formation of the upper wiring line layer 32, an inter-layerinsulating layer is formed on an entire surface and polishing isperformed by, for example, a CMP method, whereby a trench portionoccurring by the process of FIG. 48 is filled with the inter-layerinsulating layer (the present process is not illustrated). Due to theabove processes, the connection unit 21 is completed.

FIG. 49 is a view that omits the etching-dedicated mask and the variableresistance layer 40 from a state of FIG. 48 to clarify relationships ofelectrical connection. The first penetrating electrode 50 penetrates thelower wiring line layer 30 to be connected to the peripheral circuitlayer 12, without being connected to either of the upper wiring linelayer 32 and the middle wiring line layer 31. The select gate line SGLis connected to the peripheral circuit layer 12 downward of the lowerwiring line layer 30, via the third penetrating electrode 97, the firstwiring line pattern 101 of the upper wiring line layer 32, the fourthpenetrating electrode 98, and the second penetrating electrode 52.

Next, manufacturing processes of an entirety including the cell arrayunit 20 and the connection unit 21 will be described with reference toFIGS. 68 to 82. In order to render processes more easily seen, theetching mask and portions duplicating previous descriptions areappropriately omitted from description. First, as shown in FIG. 68, theinsulating layers 60 and the WL layers 61 are stacked alternately, andthe word line stacked structure 62 is formed. The present processcorresponds to the processes of FIGS. 10 and 25.

Next, as shown in FIG. 69, the word line stacked structure 62 atportions thereof not covered by either of the first mask 80 and thesecond mask 82 described in the formation process of the connection unit21 is etched to a lowermost layer by RIE technology, and a penetratingelectrode-dedicated opening 83 is formed. The present processcorresponds to the process of FIG. 29. In the present process, the cellarray unit 20 is not influenced by the etching since it is entirelycovered by the first mask 80.

Next, as shown in FIG. 70, formation of the WL stepped portion 91 isperformed. The present process corresponds to the process of FIG. 66. Inthe present process, the cell array unit 20 is not influenced by theetching since it is entirely covered by the first mask 80.

Next, as shown in FIG. 71, a via material is filled in the openingformed in FIGS. 69 and 70, and the first penetrating electrode 50 andthe second penetrating electrode 52 are formed. The present processcorresponds to the processes of FIGS. 38 and 67.

Next, as shown in FIG. 72, the word line stacked structure 62 is batchprocessed by RIE technology, and a stripe shaped pattern of word linesWL is formed. The present process corresponds to the processes of FIGS.12 and 39. Next, as shown in FIG. 73, the layer 64 of a resistancechanging material is formed uniformly. The present process correspondsto the processes of FIGS. 13 and 40. Next, as shown in FIG. 74, fillingthe bit line film 65 is performed. The present process corresponds tothe processes of FIGS. 14 and 41. Next, as shown in FIG. 75,photolithography technology and RIE technology are employed to patternthe bit line film 65 into a pillar shape. The present processcorresponds to the processes of FIGS. 15 and 42.

Next, as shown in FIG. 76, formation of the silicon layers 66 to 68 issequentially performed. After the silicon layers 66 to 68 have beencrystallized by annealing, photolithography technology and RIEtechnology are employed to form a stripe shaped pattern extending in theY direction. After formation of an inter-layer insulating film, as shownin FIG. 77, photolithography technology and RIE technology are employedto form a stripe shaped pattern extending in the X direction. The abovedescribed processes correspond to the processes of FIGS. 17 and 18. Atthis time, a trench portion which is later to be a pattern for formingthe select gate lines SGL is formed in an inter-layer insulating filmnot illustrated, in the connection unit 21.

Next, as shown in FIG. 78, formation of the gate insulating film 44 isperformed. The present process corresponds to the process of FIG. 20.Subsequently, as shown in FIG. 79, the conductive film 72 is filled inthe trench portion of the inter-layer insulating film (not illustrated)formed in the formation processes of the silicon layers 66 to 68, andthe select gate line SGL is formed. The present process corresponds tothe process of FIG. 43.

Next, as shown in FIG. 80, a portion that is to be the connection regionwith the upper wiring line layer 32 (the third penetrating electrode 97)of the select gate lines SGL is left, and the other select gate linesSGL are etched back. At this time, the select gate lines SGL of the cellarray unit 20, and not only those of the connection unit 21, are alsosimultaneously etched back. By sharing the etching back process of theselect gate lines SGL in the cell array unit 20 and the formationprocess of the third penetrating electrode 97 in the connection unit 21in this way, processes can be made simpler, compared to when formingeach of the units independently. The present process corresponds to theprocesses of FIGS. 21 and 46.

Next, as shown in FIG. 81, lithography technology and RIE technology areemployed to provide an opening upwardly of the second penetratingelectrode 52 in the connection unit 21, and form the fourth penetratingelectrode 98. The present process corresponds to the process of FIG. 47.Next, as shown in FIG. 82, formation of the global bit line GBL in thecell array unit 20 and formation of the upper wiring line layer 32(first wiring line pattern 101 and second wiring line pattern 102) inthe connection unit 21 are performed simultaneously. The present processcorresponds to the processes of FIGS. 24 and 48. Due to the aboveprocesses, the semiconductor memory device according to the presentembodiment is completed.

FIRST MODIFIED EXAMPLE

The present embodiment described an example where one of the select gatelines SGL in the connection unit 21 is connected to the fourthpenetrating electrode 98 via the first wiring line pattern 101 of theupper wiring line pattern 32. However, a specific configuration of theconnection unit is not limited to the above-described configuration.Described below are modified examples in which configurations of themiddle wiring line layer 31 and the upper wiring line layer 32 of theconnection unit 21 are changed.

FIG. 83 is a perspective view of external appearance of a connectionunit 21 of a semiconductor memory device according to a first modifiedexample. Contrary to in the first embodiment (FIG. 8), the first wiringline pattern 101 extending in the Y direction is not formed in the upperwiring line layer 32, and instead, a third wiring line pattern 104 isformed in the upper wiring line layer 32. Both ends of the third wiringline pattern 103 are connected to the select gate line SGL via the thirdpenetrating electrode 97, and a central portion of the third wiring linepattern 103 is connected to the second penetrating electrode 52 via thefourth penetrating electrode 98.

That is, the third wiring line pattern 104 connects fellow select gatelines SGL and connects said select gate lines SGL and the secondpenetrating electrode 52, thereby playing a role combining those of thefirst wiring line pattern 101 and the second wiring line pattern 102 inthe first embodiment. As a result, the select gate line SGL positioneddirectly above the second penetrating electrode 52 can be connected tothe peripheral circuit layer 12 downward of the lower wiring line layer30.

SECOND MODIFIED EXAMPLE

FIG. 84 is a perspective view of external appearance of a connectionunit 21 of a semiconductor memory device according to a second modifiedexample, and FIGS. 85A to 85C are perspective views rendering parts ofFIG. 84 visible. FIG. 85A omits display of the upper wiring line layer32. FIG. 85B further omits display of the middle wiring line layer 31from FIG. 85A. FIG. 85C further omits display of the fourth penetratingelectrode 98 from FIG. 85B.

As shown in FIG. 84, in the present modified example, contrary to in thefirst embodiment (FIG. 8), three first wiring line patterns 101extending in the Y direction are formed in the upper wiring line layer32. The three first wiring line patterns 101 are respectively connectedto the third through fifth from front select gate lines SGL via thethird penetrating electrode 97. Moreover, the center one of the threefirst wiring line patterns 101 is connected to the second penetratingelectrode 52 via between the second from rear select gate lines SGL, andthe two side ones of the three first wiring line patterns 101 areconnected to the second penetrating electrode 52 via between the fourthfrom rear select gate lines SGL (refer to FIGS. 85A and 85B).

In addition, as shown in FIG. 85C, in the present modified example, twosecond penetrating electrodes 52 penetrating the lower wiring line layer30 up and down are formed sandwiching the base portion 120 of the wordline WL not only at an end of the WL stepped portion 91 but also at aposition one to the front thereof. Increasing the number of secondpenetrating electrodes 52 in this way makes it possible to increase thenumber of contacts connecting the middle wiring line layer 31 and upperwiring line layer 32 and the peripheral circuit layer 12.

Moreover, increasing the number of first wiring line patterns 101 in theupper wiring line layer 32 makes it possible to connect a greater numberof select gate lines SGL to the peripheral circuit layer 12 in oneconnection unit 21. In this case, increasing the number of second wiringline patterns 102 makes it possible to handle an increase in the numberof first wiring line patterns 101 and fourth penetrating electrodes 52.Appropriately combining the first wiring line pattern 101 for connectingthe third penetrating electrode 97 and the fourth penetrating electrode98, and the second wiring line pattern 102 acting as a bypass pattern inthis way makes it possible to achieve contact with the peripheralcircuit layer 12 while maintaining design freedom.

THIRD MODIFIED EXAMPLE

FIG. 86 is a perspective view of external appearance of a connectionunit of a semiconductor memory device according to a third modifiedexample. Contrary to in the first embodiment, the third penetratingelectrode 97 that connects the select gate line SGL and the upper wiringline layer 32 is not formed. The upper wiring line layer 32 is connectedto a further upwardly positioned wiring line layer via a fifthpenetrating electrode 105. The fifth penetrating electrode 105 isconnected to one end of a wiring line pattern 106 extending in the Ydirection, and the other end of the wiring line pattern 106 iselectrically connected to the second penetrating electrode 52 via thefourth penetrating electrode 98.

The present modified example makes it possible to electrically connect awiring line layer positioned more upwardly than the upper wiring linelayer 32 to the peripheral circuit layer 12 via the fifth penetratingelectrode 105 and the wiring line pattern 106. Moreover, configurationsaccording to the above-described first embodiment and first throughthird modified examples may be appropriately adopted in combination. Asa result, space increase of the connection unit 21 can be suppressedwhile securing freedom of design.

Other Embodiments

While certain embodiments of the inventions have been described, theseembodiments have been presented by way of example only, and are notintended to limit the scope of the inventions. Indeed, the novel methodsand systems described herein may be embodied in a variety of otherforms; furthermore, various omissions, substitutions and changes in theform of the methods and systems described herein may be made withoutdeparting from the spirit of the inventions. The accompanying claims andtheir equivalents are intended to cover such forms or modifications aswould fall within the scope and spirit of the inventions.

What is claimed is:
 1. A semiconductor memory device, comprising: a cellarray unit; and a connection unit that is provided adjacently to thecell array unit and is electrically connected to a peripheral circuitunit disposed below the cell array unit, the cell array unit including:a plurality of word lines that extend in a first direction and arerespectively disposed with a certain spacing in a second direction and athird direction, the second direction intersecting the first direction,and the third direction being a stacking direction that intersects thefirst direction and the second direction; a plurality of bit lines thatextend in the third direction and are respectively disposed with acertain spacing in the first direction and the second direction; avariable resistance layer that is provided on a side surface facing theword line in the bit line and that functions as a storage element at anintersection of the bit line and the word line; a plurality of selectgate lines that are provided in a layer upward of the plurality of wordlines and that function as a control gate for selecting the bit line;and a plurality of global bit lines that are provided in a layer upwardof the plurality of select gate lines and that are electricallyconnected to the plurality of bit lines via the control gate, and theconnection unit including: a lower wiring line layer electricallyconnected to the plurality of word lines; a middle wiring line layerthat is provided on the lower wiring line layer and in which theplurality of select gate lines extending from the cell array unit areformed; and an upper wiring line layer that is provided on the middlewiring line layer and in which the same wiring line layer as theplurality of global bit lines is formed, the lower wiring line layerincluding: a first penetrating electrode that connects the plurality ofword lines and the peripheral circuit unit; and a second penetratingelectrode that connects at least one of the middle wiring line layer andupper wiring line layer and the peripheral circuit unit.
 2. Thesemiconductor memory device according to claim 1, wherein the connectionunit includes a third penetrating electrode that connects the middlewiring line layer and the upper wiring line layer, and the thirdpenetrating electrode is formed by the same material as the middlewiring line layer.
 3. The semiconductor memory device according to claim2, wherein the third penetrating electrode is formed integrally with themiddle wiring line layer.
 4. The semiconductor memory device accordingto claim 2, wherein the connection unit includes a fourth penetratingelectrode that connects the upper wiring line layer and the secondpenetrating electrode, and the fourth penetrating electrode is formed bya different material from the third penetrating electrode.
 5. Thesemiconductor memory device according to claim 4, wherein the middlewiring line layer is electrically connected to the second penetratingelectrode via the third penetrating electrode, the upper wiring linelayer, and the fourth penetrating electrode.
 6. The semiconductor memorydevice according to claim 5, wherein the upper wiring line layerincludes a first wiring line pattern that connects the third penetratingelectrode and the fourth penetrating electrode, and the first wiringline pattern is formed extending in the second direction.
 7. Thesemiconductor memory device according to claim 6, wherein the upperwiring line layer includes a second wiring line pattern that bypasses aconnection portion between the first wiring line pattern and the fourthpenetrating electrode, and both ends of the second wiring line patternare respectively connected to the middle wiring line layer.
 8. Thesemiconductor memory device according to claim 1, wherein the connectionunit includes: a fourth penetrating electrode that connects the upperwiring line layer and the second penetrating electrode; and a fifthpenetrating electrode that connects the upper wiring line layer and awiring line layer formed more upwardly than the upper wiring line layer,and the fifth penetrating electrode is electrically connected to thefourth penetrating electrode via the upper wiring line layer.
 9. Thesemiconductor memory device according to claim 1, wherein the pluralityof word lines form a comb tooth shaped pattern by extending from thebase portion formed in the connection unit to both sides of the firstdirection, and the first penetrating electrode is provided between thecomb tooth shaped patterns that face each other in the first direction.10. The semiconductor memory device according to claim 1, wherein theplurality of word lines form a comb tooth shaped pattern by extendingfrom the base portion formed in the connection unit to both sides of thefirst direction, and the second penetrating electrode is providedbetween the comb tooth shaped patterns that are adjacent in the seconddirection.
 11. The semiconductor memory device according to claim 1,wherein the first penetrating electrode includes: a first columnarportion that penetrates the lower wiring line layer in the thirddirection and that connects the peripheral circuit unit and an uppersurface of the lower wiring line layer; a second columnar portion thatpenetrates part of the lower wiring line layer in the third directionand that connects the word line and the upper surface of the lowerwiring line layer; and a bridging portion that connects the firstcolumnar portion and the second columnar portion at the upper surface ofthe lower wiring line layer.
 12. The semiconductor memory deviceaccording to claim 11, wherein a plurality of connection regions inwhich the second columnar portion and the word line are connected areformed in a stepped shape in the second direction, and a plurality ofthe first penetrating electrodes are each connected to a different wordline by the plurality of connection regions.
 13. A method ofmanufacturing a semiconductor memory device, comprising: forming a lowerwiring line layer, the lower wiring line layer including a word linestacked structure in which a plurality of insulating layers and aplurality of word line layers are alternately stacked; forming a firstthrough-hole in a connection unit of the lower wiring line layer, theconnection unit being connected to a peripheral circuit unit disposeddownwardly of the lower wiring line layer, and the first through-holepenetrating the lower wiring line layer up and down; forming a secondthrough-hole in the connection unit, the second through-hole reachingfrom an upper surface of the lower wiring line layer to each layer ofthe plurality of word line layers; supplying a via material to the firstthrough-hole and the second through-hole and respectively forming afirst penetrating electrode and a second penetrating electrode, thefirst penetrating electrode connecting the plurality of word lines andthe peripheral circuit unit, and the second penetrating electrodeconnecting the wiring line layer formed upwardly of the lower wiringline layer and the peripheral circuit unit; in a cell array unit that isadjacent in a first direction to the connection unit of the lower wiringline layer, patterning the word line stacked structure and forming aplurality of word lines that extend in the first direction, with acertain spacing in a second direction, the second direction intersectingthe first direction; forming a variable resistance layer on a sidesurface of the plurality of word lines, the variable resistance layerfunctioning as a storage element; forming between the variableresistance layers a plurality of bit lines that extend in a thirddirection, with a certain spacing in the first direction and the seconddirection, the third direction being a stacking direction thatintersects the first direction and the second direction; forming amiddle wiring line layer upwardly of the lower wiring line layer, themiddle wiring line layer being formed straddling the cell array unit andthe connection unit, and the middle wiring line layer including aplurality of select gate lines that each function as a control gate forselecting the bit line; forming an upper wiring line layer upwardly ofthe middle wiring line layer, the upper wiring line layer including aplurality of global bit lines that are electrically connected to theplurality of bit lines via the control gate; and connecting at least oneof the middle wiring line layer and upper wiring line layer and thesecond penetrating electrode.
 14. The method of manufacturing asemiconductor memory device according to claim 13, further comprising:forming a third penetrating electrode that connects the middle wiringline layer and the upper wiring line layer, wherein the thirdpenetrating electrode is formed by after forming the middle wiring linelayer, etching back the middle wiring line layer excluding a regionwhere the third penetrating electrode is formed.
 15. The method ofmanufacturing a semiconductor memory device according to claim 14,further comprising: forming a fourth penetrating electrode that connectsthe upper wiring line layer and the second penetrating electrode,wherein the fourth penetrating electrode is formed by a differentmaterial from the third penetrating electrode.
 16. The method ofmanufacturing a semiconductor memory device according to claim 15,wherein the fourth penetrating electrode is formed by forming an openingin an inter-layer insulating film formed in the middle wiring line layerand filling a metallic material in said opening.
 17. The method ofmanufacturing a semiconductor memory device according to claim 13,further comprising: during forming the first through-hole, forming afirst mask on an upper surface of the word line stacked structure, thefirst mask being provided with an opening that straddles predeterminedformation positions of both of the first through-hole and the secondthrough-hole; forming a second mask on an upper surface of the firstmask, the second mask covering the predetermined formation position ofthe second through-hole; and etching a portion not covered by either ofthe first mask and the second mask to form the first through-hole. 18.The method of manufacturing a semiconductor memory device according toclaim 17, further comprising: after forming the first through-hole,shrinking the second mask; and forming a first sidewall protecting filmon the inside of the first through-hole and on a side surface of theshrunk second mask, the first sidewall protecting film being forprotecting a sidewall of the first through-hole.
 19. The method ofmanufacturing a semiconductor memory device according to claim 18,further comprising: after forming the second through-hole, forming asecond sidewall protecting film in a region that includes the inside ofthe second through-hole and an intermediate region between the firstthrough-hole and the second through-hole, the second sidewall protectingfilm being for protecting the second through-hole.
 20. The method ofmanufacturing a semiconductor memory device according to claim 19,further comprising: during forming the first penetrating electrode,supplying the via material to the first through-hole, the secondthrough-hole, and the intermediate region etched during forming thesecond through-hole, thereby simultaneously forming: a first columnarportion of the first penetrating electrode that is formed in the firstthrough-hole; a second columnar portion of the first penetratingelectrode that is formed in the second through-hole; and a bridgingportion that connects the first columnar portion and the second columnarportion at the upper surface of the word line stacked structure.